One astronomer communicated with another, and a general exchange of advice began. In a short while, a communication was laid on the desk of the President of the United States, who scanned it and had it immediately transmitted to the Secretary General of the United Nations. The Secretary General circulated the report among the scientific bureaus of all member nations, and this led in turn to a meeting of the Security Council. This meeting was held in quiet, without benefit of newspaper reporters or audience.
There was no longer any doubt. The radiation of the Sun reaching the face of the Earth had decreased. The facts were indisputable. Where a day should have registered, in some places, at least 90° in the Sun, a reading of only 84° was noted. Measurements definitely showed that the face of the Sun visible to man on Earth had dimmed by just that margin.
This might not prove serious at first, but as the scientists called in by the Security Council pointed out, it promised terrible things as the year went on. A difference of five or ten degrees all over the Earth could mean the ruin of certain crops, it could mean an increase in snowfall and frost that could very rapidly destroy the economies and habitability of many places on the Earth's teeming surface.
"But what," asked the Chairman of the Council, "is causing this decrease in solar energy?"
This the astronomers could not answer. But they pointed to one factor. The reports from the U.S. Moon Base did not agree with the observations from Earth. Moon instruments claimed no decrease whatsoever in the amount of sunlight reaching the arid, airless surface of the Earth's only satellite.
The cause was somewhere on Earth. And the Security Council requested the careful scanning of the Earth from space platforms and the Moon to determine the center of the trouble.
Burl Denning had not found the next valley of much interest, either. Evidence of an Inca road over the mountain had petered out. There were signs there had been human dwellings, but they were not Inca—just reminders of the onetime passage of an unknown band of primitives who had grazed their sheep, built temporary tents, and pulled up stakes perhaps a hundred years before.
So again at night, Burl, his father, and Gonzales took counsel. They were debating which way to proceed next; Mark Denning reasoning that they should go further inland, following tales natives had told; Gonzales urging that they retrack their path and proceed northward toward the regions where Inca ruins abounded.
For the past week Burl had not been able to get radio reception. The static had increased as they had gone eastward over the mountain, but not a word of news or any human voice came through. The Moon was rising on the horizon as Burl sat playing with the antenna. Finally he gave up and switched it off.